The present invention relates to a vehicular lamp and, more particularly, to a vehicular lamp that uses a light-emitting diode light source to permit easy control the set lighting pattern, to provide enhanced heat dissipating effect, to reduce the weight, and to increase the sense of quality after assembly.
Vehicular lamps have been developed from conventional halogen lamps to high-intensity discharge (HID) lamps and then to light-emitting diode (LED) lamps. LED lamps for vehicles do not include stabilizers required in HID lamps and consume less energy while having the advantages of small volume, light weight, high on/off speed, excellent resistance to vibration, and long service life.
However, LED lamps must work in a suitable temperature condition to provide reliable use. The emitting efficiency of LED chips deteriorates at high temperature which even damages the LED chips. The working temperature for LED chips is preferably below 80° C. Thus, highly efficient heat dissipation of the LED lamps is the key factor of smooth operation of the LED lamps.
Conventional vehicular lamps include LEDs, a reflective cover, and a housing. The housing is preferably made of metal with good strength and thermal dissipation properties. The housing includes a recessed portion in a center thereof. A light-transmittable shield is mounted in front of the recessed portion. The reflective cover is mounted in the recessed portion of the housing and includes an inner recessed portion with a reflective face. The LEDs are mounted in the inner recessed portion such that the light rays emitted by the LEDs can be reflected by the reflective face and then transmit the housing to present a set lighting pattern.
The LEDs are generally fixed on a cooling block for cooling purposes. The cooling block is coupled to the housing such that the heat generated by the LEDs can indirectly be conducted by the cooling block to the housing for dissipating the heat. However, the indirect heat conduction causes a loss in the heat dissipating efficiency. Although the housing can protect the reflective cover, the vehicular lamp has a larger weight due to the heavy metal housing, which is disadvantageous to reduction of the weight of the vehicle and to the energy-saving demand.